Bump spring from 2.1.0 to 2.1.1

Bumps [spring](https://github.com/rails/spring) from 2.1.0 to 2.1.1.
- [Release notes](https://github.com/rails/spring/releases)
- [Changelog](https://github.com/rails/spring/blob/master/CHANGELOG.md)
- [Commits](rails/spring@v2.1.0...v2.1.1)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Author: dependabot-preview[bot]

Gemfile.lock

@@ -373,7 +373,7 @@ GEM
       simplecov-html (~> 0.11)
     simplecov-html (0.12.2)
     slop (3.6.0)
-    spring (2.1.0)
+    spring (2.1.1)
     spring-watcher-listen (2.0.1)
       listen (>= 2.7, < 4.0)
       spring (>= 1.2, < 3.0)